The presence of foreign materials in food products is a significant concern to food processors. Naturally occurring foreign materials, however, pose a special challenge. An example of a naturally occurring foreign material is bone, which can typically occur in the product because of processing techniques or product variation. The concern over the presence of bone in a processed food product is most evident in the poultry industry, as the industry has steadily moved towards further processed or value added products (i.e., deboned poultry products).
The occurrence of bone in poultry fillets is undesirable in many respects. First, there is concern regarding the potential liability of producers if consumers swallow bones that could prove to be harmful. Second, there is a concern for customer satisfaction. In general, poultry sellers receive two complaints for every million pounds of product, which results in approximately 230 complaints for the year. As a result, the customers of most poultry suppliers of deboned product are now placing additional pressures on suppliers to reduce the incidence of bones.
Poultry suppliers have attempted to address the incidence of bones by implementing both manual and automated deboning processes. Research has shown that both manual and automated deboning processes are not perfect, and bones occur in the product using either the manual or automated process at rates that could be of concern. For example, Smith inspected 300,299 pounds of fillets, of which 379 bones were found. (1) Similarly, in inspecting 186,310 pounds of tenders, 428 bones were found. The predominant bone found in these tests was the clavicle; however, there were also no discernable differences between the amount of bones found when the deboning processes are compared (manual to automated).
From a quality control perspective, the ability to detect these bones would also improve production efficiencies by helping to reduce the possibility of rework while optimizing yield. Currently, two inspection techniques for monitoring bone in food products are in use: manual palpitation and X-ray screening. Besides being both time-consuming and expensive processes, manual palpitation and X-ray screening techniques have additional shortcomings Manual palpitation techniques are labor-intensive and repetitive. It is well known that whenever humans perform any repetitive job such as this, they eventually lose their concentration and become less effective at conducting the task over time, which leads to errors. In addition, manual palpitation techniques pose the risk of microbial contamination. X-ray screening techniques have also been problematic. Natural variations in thickness in food products combined with changes in meat product properties (meat/bone calcification) over time, can lead to errors in the detection. In addition, X-ray images are typically low contrast, and it is challenging to construct algorithms that can accommodate the natural variations in a global sense. Furthermore, X-ray screening systems provide additional issues related to product presentation for X-ray interrogation, as well as concerns over the life of the X-ray tube and sensor.
Perhaps the greatest limitation in the manual palpitation and X-ray screening techniques is that neither of these techniques allows for the ability to perform real time quality and process control as there is no mechanism to provide feedback to the deboning process in a timely way. Accordingly, there is a need for a screening approach as part of the deboning process that would be capable of reducing the occurrence of bones as well as provide real time quality and process control. It is to the provision of such a screening approach that the various embodiments of the present invention are directed. In a similar vein, the ability to guide machinery to accommodate for the variability of natural anatomy requires the identification of relevant anatomical structures, such as tendons and joints.